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Properties of the sintered Sn-added stainless steels
Source publication
It was found that addition of 4 wt.% of gas-atomized tin (Sn) powder to stainless steel powders
could alter sintered properties of P/M stainless steels. For stainless steel series 300 powders, Sn powder
addition resulted in improved tensile properties and hardness. It was speculated that the liquid Sn, formed
during sintering process, acted as eith...
Contexts in source publication
Context 1
... of steel types, sintered densities of the sintered 4 wt. % Sn-added stainless steels were slightly lower than those of the sintered straight stainless steels (Table 1). For the case of sintered series 300 materials, lower sintered density may be attributed to pore size expansion due to the liquid tin accelerate atomic diffusion whereas that of the series 400 materials is due to additional pores caused by Sn particle disappearance (see # (3.2) microstructure). ...
Context 2
... experimental P/M processing conditions employed in this study, addition of 4 wt. % Sn powder to stainless steels series 300 powders resulted in significantly improved mechanical properties (Table 1). In contrast, addition of Sn powder to stainless steel series 400 powders caused extremely adverse effects on tensile properties. ...
Citations
... Sn powder addition improves tensile properties and hardness. Sintering activation is also initiated, because the liquid Sn acts as a diffusion factor between the particles(Nattaya et al., 2008). ...
The objective of this study is to recycle AA6061 and develop a new process. The optimum method of producing a smaller particle size was by using a planetary ball mill machine. Three rotation speeds, namely, 300, 350, and 400 R.P.M, were used to produce the particles. A series of studies was conducted to determine the mechanical properties, physical properties, heat treatment process, and wear resistance and to develop model prediction of wear resistance with silica reinforcement. In the first study, three particle sizes, namely, 25, 63, and 100 µm, were sieved of the milled product to characterize its bulk properties of the compression strength. Results showed that the mix of 25 and 100 µm is the optimal compression strength. Then, two groups were selected to study the effect of mixture particles 25 +100 µm and 25 +63 µm. Higher value of compression strength was observed by using 25 + 100 µm which was 195.6 MPa. In the second study, heat treatment of the best compound was conducted to investigate the effect of the quenching and aging processes on compression strength. The heat treatment process was implanted with the quenching temperature of 530 °C for 2 h, thus the aging temperature is 175 °C with various aging holding time. Five aging holding times, namely, 2, 4, 6, 8, and 10 h, were selected.. The optimal aging holding time is 4 h, then the compression strength was 300 MPa. Finally, wear test was conducted for the milled product. Four groups were classified for the wear test. The first group was the as-fabricated milled product. The second group was obtained by optimal heat treatment. The third group used graphite as a reinforcement material. The last group used silica as a reinforcement material. The results indicated that the specimens reinforced by silica material have the highest wear resistance because of their high microhardness value. The prediction of volume loss was developed based on the reinforcement of silica material.
In conclusion, the recycling aluminum chips process is successfully done by using 25 + 100 µm particle size reinforced by silica and treated with heat treatment.
... In addition, the addition of metal element could improve the ductile of stainless steel. For instance, the addition of Sn not only improved the yield strength of 316 L stainless steel, but also increased the elongation [29]. However, since the amount of Cu is very small in this work, addition of Cu is unlikely to be the main factor. ...
Graphene (Gr) can significantly improve the mechanical properties of metal matrix materials. However, the reinforcing effect of Gr on stainless steel (SS) has rarely been investigated due to the difficulty in its uniform dispersion. In this study, 316L stainless steel was reinforced with copper-coated graphene (Gr-Cu/SS) through molecular level mixing, ball milling, and spark plasma sintering (SPS). The tensile strength and yield strength of Gr-Cu/SS have increased by 74.0% and 65.5%, respectively, with 0.2 wt% graphene added. The improvement on the tensile strength and yield strength of Gr-Cu/SS is attributed to the effective load transfer and the increase of relative density due to the addition of graphene. Moreover, the corrosion resistance of Gr-Cu/SS was improved, attributed to the low cathodic overvoltage of copper and the prevention of ionic transfer between stainless steel grains by graphene. Keywords: Graphene, Stainless steel, Powder metallurgy, Mechanical properties, Spark plasma sintering
... These mixed powders were prepared for liquid-phase sintering in the first sintering. The addition of low-melting-point Cu-Sn powders in the sintering processes, which also increases the sintering properties, has also been investigated experimentally (Tosangthum, et al.,2008). ...
Sintered materials are commonly used in industrial equipment, including bearing components. These materials include bimetals consisting of steel backed sintered bronze lined bushings. In particular, 90Cu-10Sn (mass%) bronze is widely used in bearing components. Lead bronze, in which the lead serves as a solid lubricant, is being replaced with other materials, among which are sulfide-dispersed bronzes. In sulfide-dispersed bronze, sulfides instead of lead play the role of solid lubricant. However, the sulfides in the bronze may be subject to chemical reduction during sintering, especially when this is carried out under a reducing atmosphere containing hydrogen gas. In this study, we investigate the effect of the sulfides on the bronze, with a focus on the hardness of the bronze matrix and the reaction between sulfides and hydrogen gas. Water-atomized powders were prepared for comparison of the sintering behavior. The sintering temperature in the tests was 1123 K. From the phase diagram of the Cu-Sn system, the liquid phase starts to form into bronze containing 20 mass% Sn at approximately 1123 K; thus, some conditions undergo liquid-phase sintering. Sulfides are observed to disappear from sintered bronze surfaces under a reducing atmosphere. However, the sulfides that are not in a solid solution do not affect the hardness of the bronze matrix, which does, however, depend on the tin content.
A new family of resource-saving ferritic stainless steels, with the composition of 17Cr-xSn (x50.1- 0.4 wt-%) have been developed by examining the effect of Sn on high temperature ductility, the corrosion resistance properties and the passivation film structure. The results show that tinbearing stainless steel obtains superb plasticity and there is no evidence of tin-containing precipitation in the fracture facets. High temperature brittleness at about 900uC is caused by the carbide or nitride precipitation along the grain boundary or inside. The precipitation in the grain boundary hinders the free movement of dislocation, thus increasing the strength and decreasing the toughness of steel. The polarisation curves and weight loss measurement indicate that the corrosion resistance of stainless steel is improved by adding small amount of Sn. The existence of Sn in passivation film suppresses the anodic dissolution of steels during long exposure to the aggressive solution, and the dense rust layer is thick enough to protect the steel and strongly inhabit the ingress of the solution.
The present study describes tribological properties of copper based porous alloy containing nano-sized sulfide particles. The porous alloy was fabricated with sintering on the steel plate using the developed powders consisted from Cu with dispersed sulfides. The micro structure of the alloys consisted from micro sized open pores and sintered particles. The measurement of tribological properties were carried out with a ring on disc testing apparatus with a steel ring as the mating specimen. First, comparison of friction behavior between the developed material and the lead-bronze alloy used as traditional materials for bearings are evaluated. As results, the friction coefficient of the developed material was stable and lower than that of the lead one and larger adhesion resulted in the higher friction resistance was found on the ring surface. In order to enhance porous structure on the reduction and stabilization of the friction resistance, graphite powder was penetrated into the pores by rubbing with the graphite rod. It was found that the further reduction of friction resistance was obtained.
